Quantitation of binding of factor VIII antigen to concanavalin A.
This study establishes a convenient method for screening plasma samples for abnormalities of the carbohydrate content of the factor VIII (FVIII) molecule. A radioimmuno-electrophoretic technique has been developed to quantitate the percentage binding of FVIII-related antigen (VIII-Ag) to the lectin concanavalin A (Con A). Plasma samples were electrophoresed through a strip of agarose containing Con A into agarose containing a mixture of unlabelled anti-FVIII and 125I-anti-FVIII where precipitant lines formed, the height of which was dependent upon the degree of VIII-Ag binding to Con A in the first gel. Using this system reduced binding of VIII-Ag to  Con A was found in the plasma of 12 patients with moderate classical von Willebrand's disease  (vWd), while the Con A binding of six haemophilia A patients fell within the normal range. The VIII-Ag in normal cryoprecipitate showed increased % binding to Con A while the VIII-Ag remaining in the cryo-supernate demonstrated reduced Con A % binding.
D000941:Antigens / Q000032:analysis; D002241:Carbohydrates / Q000032:analysis; D003208:Concanavalin A / Q000378:metabolism*; D005169:Factor VIII / Q000276:immunology / Q000378:metabolism*; D006467:Hemophilia A / Q000097:blood / Q000276:immunology; D006801:Humans; D007123:Immunoelectrophoresis, Two-Dimensional; D014842:von Willebrand Diseases / Q000097:blood / Q000276:immunology
D000941:Antigens; D002241:Carbohydrates; D003208:Concanavalin A; D005169:Factor VIII